If your wave is tall but short, you need to add more weight to the center and front. Also, try bumping your speed up in .5MPH increments. My wave is pretty good with 0% to 25% tab, much past 50% I think will kill it. (My son the surf king, I use this to mess with him, tab slowly down to100% and the wave just goes away, for him, he prefers as much length as possible, vs. height, this gives him a good run into a 360 and allows for him to wash back on the turn and still stay in the pocket.) The water depth will also have some effect.

I would also suggest dialing it in without a surfer, you can see what is going on much better than when the board/rider is creating some wash etc.

Here is a video of his first 360 landed last year, you can see he takes a good run at to pull it off. Way beyond my ability...